1. Field of the Invention
The present invention relates to surgical instruments and, particularly, to an instrument for biopsy sampling of tissue. Still more particularly, the present invention relates to an endoscopic biopsy instrument that obtains core biopsy samples and integrates two or more biopsy-sampling modalities.
2. Background of Related Art
Biopsy is the removal and study of body tissue for medical diagnosis. Typically, physicians obtain biopsy samples in order to detect abnormalities such as cancer and determine the extent to which cancerous tissue has spread. They use various biopsy instruments to acquire tissue samples from different areas of the body. Many current biopsy instruments, however, cannot retrieve full core samples of tissue, do not provide versatility in sampling methods, or are overly intricate in design and manufacture.
During a biopsy tissue-sample procedure performed on a body lumen, a physician generally uses an endoscope to provide a passageway for entry of the biopsy instrument into the body. Having thus secured access to the biopsy site, the physician uses some device to extract a tissue sample from the wall of the target body lumen. Usually, the walls of body lumen, such as the esophagus, the gastrointestinal tract, or the urinary tract, have three layers: the surface mucosal or epithelial layer comprised of mucus; the submucosal layer, which is below the mucosal layer; and the muscle layer. Many current biopsy devices can only take tissue from the surface mucosal layer and also cannot retrieve full core samples.
In many situations, physicians may desire full core samples because, with larger cross-sections of tissue types, they can more accurately determine the extent to which cancer has spread. It is also desirable to obtain full, clean core samples that have not been crushed by devices penetrating into tissue. Moreover, it may be desirable to obtain a full core sample without having to penetrate past a desired depth of tissue in order to obtain a corresponding desired depth of core sample. It would be preferable to insert a biopsy needle only as far as necessary to obtain a full core sample to minimize trauma to the patient.
Further, many current devices lack versatility. Many devices today extract tissue samples through aspiration, brush cytology, or pinch biopsy. In the case of aspiration, a physician inserts a very fine needle into the wall of the target tissue and draws fluid, typically saline, through the needle. The physician thus collects some surface tissue cells. In the case of brush cytology, a physician introduces a brush through the lumen of the endoscope to collect tissue cells by scraping the surface of the target site. In the case of pinch biopsy, a physician inserts a bioptome, having a pair of opposed jaw cups, through the lumen of the endoscope, to the tissue site. The physician may then close the jaws around the target surface and pinch away a sample from the surrounding tissue.
Typically, current devices may employ only one of these methods to obtain tissue samples. Thus, a physician who desires tissue samples obtained through both aspiration and brush cytology, for example, must insert one instrument, take a sample, retrieve the instrument, insert a second instrument, take a second sample, and then retrieve the second instrument. Such practice is time consuming and leads to procedural inefficiency.
Many current instruments also have an overly complex design. Devices that might otherwise fulfill one of the aforementioned needs, such as the need to capture core samples, for example, often employ complex cutting mechanisms held in sheaths or housings requiring very exact tolerances.
In light of the foregoing, there exists a need for a biopsy tissue-sampling device that effectively obtains a full core tissue sample, accommodates multiple sampling modes, and is simple in design and inexpensive to manufacture.